A massive dust storm forms over the Sahara and blows fine particulate dust over the Atlantic.
Dust acts as a shield and blocks sunlight from reaching the sea surface. In some cases the sea surface temperature can be reduced by 1°C from normal average temperatures. This has important consequences for hurricane and tropical cyclone formation which are very sensitive to sea surface temperatures.
It has been shown that large dust storms originating in the Sahara and blowing over the Atlantic can dramatically reduce the liklihood of tropical cyclone formation.
However there are large uncertainties in how African dust storms may change due to climate change. At present it is difficult to predict how dust emissions and transport may change over the next few decades due to global warming.
More info at :
http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2478
CLIMATE AND GEOHAZARDS 